Welding is a process of receiving of fixed connections through establishment of interatomic connections between welded parts during their local or complete heating, plastic deformation and mutual affection of one and another.
First methods of welding occurred in the origins of civilization – with the beginning of usage and processing of steel. Steel product manufacturing was widespread in the places of stratification of iron ore and non-ferrous ore.
The first welding process was the forging. Need for repair, for edition of more accomplished products lead to necessity of development and improvement of metallurgical and welding process. Welding with electricity using for steel heating has appeared with discovery of electricity, electric arc.
In 1802 Russian scientist Vasiliy Petrov discovered the phenomenon of electric arc and published data about experiments carried out with arc.
In 1881-1882 inventors N. N. Benardos and N. G. Slavyanov working independent one from each other, developed the way of connecting steel details by using welding.
In 1905 Russian scientist V. F. Mitkevich offered using electrical arc, stimulated by three-phase current, for welding. In 1919 has been invented welding with alternating current using. C. J. Holslag.
In XIX century welding processes have been improved by scientists Eliu Thomson, Edmund Davy and other. In USSR in XX century E. O. Paton, B. E. Paton and G. A. Nikolaev deal with a matter of welding. Soviet scientists were the first who studied the problem and peculiarities of welding in weightlessness and applied welding in space. First in the world welding in deep vacuum conditions in space has been performed on the 16th October in 1969 on the ship “Souz-6” by cosmonauts Georgiy Stepanovich Shonin and Valeriy Nikolaevich Kubasov.
In Russia welding questions and preparation of welding specialists is performed by institutes: Bauman Moscow State Technical University (chair “Welding and diagnostic technologies”), Moscow State Industrial University (Chair of equipment and technologies of welding manufacturing), Ural Polytechnic University, Chelyabinsk Institute of Mechanization and Electrification of Agriculture, Lugansk State Agricultural University and other. Scientific literature and magazines about welding are published.
At present time there are more than 150 types and methods of welding. There are diffecent classifications of these processes.
Thus, GOST 19521-74 provides steel welding classification according to main groups of features: physical, technical and technological.
The main physical welding feature is the form and type of energy used for receiving of welding connection. Energy form determines welding class, and its type – the type of welding.
There are three welding classes:
Thermal class: welding types performed though melting with thermal energy using – gas, arc, electron beam, laser and other.
Thermomechanical class: welding types performed though using of thermal energy and pressure – contact, diffusional, gas and arc pressing, forging and other.
Mechanical class: welding types performed though mechanical energy using – cold, rubbing, ultrasound, blast and other.
To technical features belong: method of steel protection in welding zone, process continuity, rate of its mechanization.
Classification according to technological features is determined separately for every welding type (according to electrode type, welding current type and other).
International welding types denomination
In international practice there are welding types abbreviations, stayed in international standard ISO 4063:2009 or its Russian analogue GOST R ISO 4063-2010. Some of these abbreviations are shown below:
|Numerical designation||Welding type nomination||Abbreviation used in USA|
|136||Cored wire arc welding with flux filler in active gas||FCAW-G|
|114||Cored self-protected wire arc welding||FCAW-S|
|13||Melting electrode in protective gas arc welding||GMAW|
|14||Non-consumable tungsten electrode in protective gas arc welding||GTAW|
|12||Arc welding under flux||SAW|
|111||Manual melting electrode arc welding (melting cover electrode arc welding)||SMAW|